---
title: "Tree Data - Self-Referential Records"
enterprise: true
---
Configure the grid to display structured data by providing self-referential records where each record contains a reference to the id of its parent.
This is the most performant way to provide and update hierarchical data to the grid, as the `rowData` is processed in a single pass.

## Providing Hierarchy

Each row in the data can contain a field containing the id of its parent row. The `treeDataParentIdField` property is used to specify the field containing the parent row id.

The below structure demonstrates a simple hierarchy, wherein the `treeDataParentIdField` grid option would specify `"parentId"` as the field containing the parent row id:
```
const data = [
    { id: 'A' },
    { id: 'B', parentId: 'A' },
    { id: 'C', parentId: 'A' },
    { id: 'D' },
    { id: 'E', parentId: 'D' },
    { id: 'F', parentId: 'E' },
]
```
In the above hierarchy, the 'A' row is the parent of 'B' and 'C'. The 'D' row is the parent of 'E' which is the parent of 'F'.

{% note %}
[getRowId](./row-ids/#row-ids) callback must be provided when using `treeDataParentIdField` to ensure each row has a unique identifier that can be correctly referenced.
{% /note %}

Ensure your data is correctly structured, as cycles and missing parent rows are not allowed.

For example, the following data structure would not be valid as the 'A' row is missing:

```
const data = [
    { id: 'B', parentId: 'A' },
    { id: 'C', parentId: 'A' },
]
```

The following data structure would not be valid as it creates a cycle:

```
const data = [
    { id: 'A', parentId: 'B' },
    { id: 'B', parentId: 'A' },
]
```

## Providing Group Values

When providing a self-referential hierarchy, the grid will use the row ID as the group value by default.
To provide a custom value, the field property of the `autoGroupColumnDef` grid option can be used.

The example below demonstrates a case where the `autoGroupColumnDef` field is set to `name` to display a group value:

{% gridExampleRunner title="Group Values" name="basic-example" exampleHeight=350 /%}

The following snippet demonstrates how to provide nested siblings with a custom group value:
```{% frameworkTransform=true %}
const gridOptions = {
    treeData: true,
    treeDataParentIdField: 'parentId',
    getRowId: (params) => params.data.id,
    autoGroupColumnDef: {
        field: 'name',
    },
};
```

## Supplied vs Aggregated

When using Tree Data, columns defined with an aggregation function will always perform aggregations on the group nodes.
This means any supplied group data will be ignored in favour of the aggregated values.

{% gridExampleRunner title="Aggregated Data" name="aggregated-data" exampleHeight=350 /%}

The example above uses the configuration below to demonstrate the `Desktop` row is being aggregated to show
the sum of its children (4), rather than the provided value (1), despite both columns showing the same field:
```
const gridOptions = {
    treeData: true,
    columnDefs: [
        {
            headerName: 'Aggregated (Sum)',
            aggFunc: 'sum',
            field: 'items',
        },
        {
            headerName: 'Provided',
            field: 'items',
        },
    ],
};
```

Refer to the [Aggregation](./aggregation/) page for more details.

## Next Up
Continue to the next section to learn how to configure the [Group Column](./tree-data-group-column/).